In the past, VBAP (Vector Base Amplitude Panning) is known as a technique for controlling localization of an acoustic image using multiple speakers (for example, see Non-Patent Document 1).
In the VBAP, the localization position of the acoustic image, which is the target, is expressed as a linear sum of vectors in directions of two or three speakers around the localization position. Then, the coefficient multiplying each vector in the linear sum is used as the gain of audio that is output from each speaker to perform gain adjustment, so that the acoustic image is localized at the position, which is the target.